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The test tst-strtod-underflow covers various edge cases close to the underflow threshold for strtod (especially cases where underflow on architectures with after-rounding tininess detection depends on the rounding mode). Make it use the type-generic machinery, with corresponding test inputs for each supported floating-point format, so that other functions in the strtod family are tested for underflow edge cases as well. Tested for x86_64.
463 lines
14 KiB
C
463 lines
14 KiB
C
/* Test for strtod handling of arguments that may cause floating-point
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underflow.
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Copyright (C) 2012-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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/* Defining _LIBC_TEST ensures long double math functions are
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declared in the headers. */
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#define _LIBC_TEST 1
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#define __STDC_WANT_IEC_60559_TYPES_EXT__
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#include <errno.h>
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#include <fenv.h>
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#include <float.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <tininess.h>
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#include "tst-strtod.h"
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/* Logic for selecting between tests for different formats is as in
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tst-strtod-skeleton.c, but here it is selecting string inputs with
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different underflow properties, rather than generated test
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data. */
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#define _CONCAT(a, b) a ## b
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#define CONCAT(a, b) _CONCAT (a, b)
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#define MEMBER(FSUF, FTYPE, FTOSTR, LSUF, CSUF) \
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const char *s_ ## FSUF;
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#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
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# define CHOOSE_ld(f,d,...) d
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#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && LDBL_MIN_EXP == -16381
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# define CHOOSE_ld(f,d,ld64i,...) ld64i
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#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && LDBL_MIN_EXP == -16382
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# define CHOOSE_ld(f,d,ld64i,ld64m,...) ld64m
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#elif LDBL_MANT_DIG == 106 && LDBL_MAX_EXP == 1024
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# define CHOOSE_ld(f,d,ld64i,ld64m,ld106,...) ld106
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#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
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# define CHOOSE_ld(f,d,ld64i,ld64m,ld106,ld113,...) ld113
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#else
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# error "unknown long double format"
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#endif
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#define CHOOSE_f(f,...) f
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#define CHOOSE_f32(f,...) f
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#define CHOOSE_d(f,d,...) d
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#define CHOOSE_f64(f,d,...) d
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#define CHOOSE_f32x(f,d,...) d
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#define CHOOSE_f128(f,d,ld64i,ld64m,ld106,ld113,...) ld113
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#if __HAVE_FLOAT64X
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# if FLT64X_MANT_DIG == 113 && FLT64X_MAX_EXP == 16384
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# define CHOOSE_f64x(f,d,ld64i,ld64m,ld106,ld113,...) ld113
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# elif (FLT64X_MANT_DIG == 64 \
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&& FLT64X_MAX_EXP == 16384 \
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&& FLT64X_MIN_EXP == -16381)
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# define CHOOSE_f64x(f,d,ld64i,...) ld64i
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# else
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# error "unknown _Float64x format"
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# endif
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#endif
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#define _XNTRY(FSUF, FTYPE, FTOSTR, LSUF, CSUF, ...) \
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CHOOSE_ ## FSUF (__VA_ARGS__),
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#define XNTRY(...) \
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GEN_TEST_STRTOD_FOREACH (_XNTRY, __VA_ARGS__)
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#define TEST(f, d, ld64i, ld64m, ld106, ld113, u) \
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{ XNTRY(f, d, ld64i, ld64m, ld106, ld113) u }
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enum underflow_case
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{
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/* Result is exact or outside the subnormal range. */
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UNDERFLOW_NONE,
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/* Result has magnitude at most half way between the largest
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subnormal value and the smallest positive normal value, and is
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not exact, so underflows in all rounding modes and independent
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of how tininess is detected. */
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UNDERFLOW_ALWAYS,
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/* Result is positive, with magnitude larger than half way between
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the largest subnormal value and the least positive normal
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value, but would underflow when rounded to nearest to normal
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precision, so underflows after rounding in all modes except
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rounding upward. */
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UNDERFLOW_EXCEPT_UPWARD,
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/* Likewise, for a negative result, underflowing after rounding
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except when rounding downward. */
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UNDERFLOW_EXCEPT_DOWNWARD,
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/* Result is positive, with magnitude at least three quarters of
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the way from the largest subnormal value to the smallest
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positive normal value, so underflows after rounding only when
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rounding downward or toward zero. */
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UNDERFLOW_ONLY_DOWNWARD_ZERO,
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/* Likewise, for a negative result, underflowing after rounding
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only when rounding upward or toward zero. */
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UNDERFLOW_ONLY_UPWARD_ZERO,
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};
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struct test
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{
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GEN_TEST_STRTOD_FOREACH (MEMBER)
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enum underflow_case c;
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};
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static const struct test tests[] =
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{
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TEST ("0x1p-126",
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"0x1p-1022",
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"0x1p-16382",
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"0x1p-16383",
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"0x1p-969",
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"0x1p-16382",
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UNDERFLOW_NONE),
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TEST ("-0x1p-126",
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"-0x1p-1022",
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"-0x1p-16382",
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"-0x1p-16383",
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"-0x1p-969",
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"-0x1p-16382",
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UNDERFLOW_NONE),
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TEST ("0x0p-10000000000000000000000000",
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"0x0p-10000000000000000000000000",
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"0x0p-10000000000000000000000000",
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"0x0p-10000000000000000000000000",
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"0x0p-10000000000000000000000000",
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"0x0p-10000000000000000000000000",
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UNDERFLOW_NONE),
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TEST ("-0x0p-10000000000000000000000000",
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"-0x0p-10000000000000000000000000",
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"-0x0p-10000000000000000000000000",
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"-0x0p-10000000000000000000000000",
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"-0x0p-10000000000000000000000000",
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"-0x0p-10000000000000000000000000",
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UNDERFLOW_NONE),
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TEST ("0x1p-10000000000000000000000000",
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"0x1p-10000000000000000000000000",
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"0x1p-10000000000000000000000000",
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"0x1p-10000000000000000000000000",
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"0x1p-10000000000000000000000000",
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"0x1p-10000000000000000000000000",
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UNDERFLOW_ALWAYS),
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TEST ("-0x1p-10000000000000000000000000",
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"-0x1p-10000000000000000000000000",
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"-0x1p-10000000000000000000000000",
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"-0x1p-10000000000000000000000000",
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"-0x1p-10000000000000000000000000",
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"-0x1p-10000000000000000000000000",
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UNDERFLOW_ALWAYS),
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TEST ("0x1.000000000000000000001p-126",
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"0x1.000000000000000000001p-1022",
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"0x1.000000000000000000001p-16382",
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"0x1.000000000000000000001p-16383",
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"0x1.000000000000000000001p-969",
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"0x1.00000000000000000000000000000000000000001p-16382",
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UNDERFLOW_NONE),
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TEST ("-0x1.000000000000000000001p-126",
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"-0x1.000000000000000000001p-1022",
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"-0x1.000000000000000000001p-16382",
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"-0x1.000000000000000000001p-16383",
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"-0x1.000000000000000000001p-969",
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"-0x1.00000000000000000000000000000000000000001p-16382",
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UNDERFLOW_NONE),
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TEST ("0x1p-150",
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"0x1p-1075",
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"0x1p-16446",
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"0x1p-16447",
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"0x1p-1075",
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"0x1p-16495",
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UNDERFLOW_ALWAYS),
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TEST ("-0x1p-150",
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"-0x1p-1075",
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"-0x1p-16446",
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"-0x1p-16447",
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"-0x1p-1075",
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"-0x1p-16495",
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UNDERFLOW_ALWAYS),
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TEST ("0x1p-127",
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"0x1p-1023",
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"0x1p-16383",
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"0x1p-16384",
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"0x1p-970",
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"0x1p-16383",
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UNDERFLOW_NONE),
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TEST ("-0x1p-127",
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"-0x1p-1023",
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"-0x1p-16383",
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"-0x1p-16384",
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"-0x1p-970",
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"-0x1p-16383",
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UNDERFLOW_NONE),
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TEST ("0x1p-149",
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"0x1p-1074",
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"0x1p-16445",
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"0x1p-16446",
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"0x1p-1074",
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"0x1p-16494",
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UNDERFLOW_NONE),
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TEST ("-0x1p-149",
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"-0x1p-1074",
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"-0x1p-16445",
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"-0x1p-16446",
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"-0x1p-1074",
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"-0x1p-16494",
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UNDERFLOW_NONE),
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TEST ("0x1.fffffcp-127",
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"0x1.ffffffffffffep-1023",
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"0x1.fffffffffffffffcp-16383",
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"0x1.fffffffffffffffcp-16384",
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"0x1.ffffffffffffffffffffffffffp-970",
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"0x1.fffffffffffffffffffffffffffep-16383",
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UNDERFLOW_NONE),
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TEST ("-0x1.fffffcp-127",
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"-0x1.ffffffffffffep-1023",
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"-0x1.fffffffffffffffcp-16383",
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"-0x1.fffffffffffffffcp-16384",
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"-0x1.ffffffffffffffffffffffffffp-970",
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"-0x1.fffffffffffffffffffffffffffep-16383",
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UNDERFLOW_NONE),
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TEST ("0x1.fffffep-127",
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"0x1.fffffffffffffp-1023",
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"0x1.fffffffffffffffep-16383",
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"0x1.fffffffffffffffep-16384",
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"0x1.ffffffffffffffffffffffffff8p-970",
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"0x1.ffffffffffffffffffffffffffffp-16383",
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UNDERFLOW_ALWAYS),
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TEST ("-0x1.fffffep-127",
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"-0x1.fffffffffffffp-1023",
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"-0x1.fffffffffffffffep-16383",
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"-0x1.fffffffffffffffep-16384",
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"-0x1.ffffffffffffffffffffffffff8p-970",
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"-0x1.ffffffffffffffffffffffffffffp-16383",
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UNDERFLOW_ALWAYS),
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TEST ("0x1.fffffe0001p-127",
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"0x1.fffffffffffff0001p-1023",
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"0x1.fffffffffffffffe0001p-16383",
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"0x1.fffffffffffffffe0001p-16384",
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"0x1.ffffffffffffffffffffffffff80001p-970",
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"0x1.ffffffffffffffffffffffffffff0001p-16383",
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UNDERFLOW_EXCEPT_UPWARD),
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TEST ("-0x1.fffffe0001p-127",
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"-0x1.fffffffffffff0001p-1023",
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"-0x1.fffffffffffffffe0001p-16383",
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"-0x1.fffffffffffffffe0001p-16384",
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"-0x1.ffffffffffffffffffffffffff80001p-970",
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"-0x1.ffffffffffffffffffffffffffff0001p-16383",
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UNDERFLOW_EXCEPT_DOWNWARD),
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TEST ("0x1.fffffeffffp-127",
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"0x1.fffffffffffff7fffp-1023",
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"0x1.fffffffffffffffeffffp-16383",
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"0x1.fffffffffffffffeffffp-16384",
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"0x1.ffffffffffffffffffffffffffbffffp-970",
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"0x1.ffffffffffffffffffffffffffff7fffp-16383",
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UNDERFLOW_EXCEPT_UPWARD),
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TEST ("-0x1.fffffeffffp-127",
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"-0x1.fffffffffffff7fffp-1023",
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"-0x1.fffffffffffffffeffffp-16383",
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"-0x1.fffffffffffffffeffffp-16384",
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"-0x1.ffffffffffffffffffffffffffbffffp-970",
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"-0x1.ffffffffffffffffffffffffffff7fffp-16383",
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UNDERFLOW_EXCEPT_DOWNWARD),
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TEST ("0x1.ffffffp-127",
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"0x1.fffffffffffff8p-1023",
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"0x1.ffffffffffffffffp-16383",
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"0x1.ffffffffffffffffp-16384",
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"0x1.ffffffffffffffffffffffffffcp-970",
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"0x1.ffffffffffffffffffffffffffff8p-16383",
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UNDERFLOW_ONLY_DOWNWARD_ZERO),
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TEST ("-0x1.ffffffp-127",
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"-0x1.fffffffffffff8p-1023",
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"-0x1.ffffffffffffffffp-16383",
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"-0x1.ffffffffffffffffp-16384",
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"-0x1.ffffffffffffffffffffffffffcp-970",
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"-0x1.ffffffffffffffffffffffffffff8p-16383",
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UNDERFLOW_ONLY_UPWARD_ZERO),
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TEST ("0x1.ffffffffffp-127",
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"0x1.fffffffffffffffffp-1023",
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"0x1.ffffffffffffffffffffp-16383",
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"0x1.ffffffffffffffffffffp-16384",
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"0x1.ffffffffffffffffffffffffffffffp-970",
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"0x1.ffffffffffffffffffffffffffffffffp-16383",
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UNDERFLOW_ONLY_DOWNWARD_ZERO),
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TEST ("-0x1.ffffffffffp-127",
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"-0x1.fffffffffffffffffp-1023",
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"-0x1.ffffffffffffffffffffp-16383",
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"-0x1.ffffffffffffffffffffp-16384",
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"-0x1.ffffffffffffffffffffffffffffffp-970",
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"-0x1.ffffffffffffffffffffffffffffffffp-16383",
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UNDERFLOW_ONLY_UPWARD_ZERO),
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};
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/* Return whether to expect underflow from a particular testcase, in a
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given rounding mode. */
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static bool
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expect_underflow (enum underflow_case c, int rm)
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{
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if (c == UNDERFLOW_NONE)
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return false;
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if (c == UNDERFLOW_ALWAYS)
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return true;
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if (TININESS_AFTER_ROUNDING)
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{
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switch (rm)
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{
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#ifdef FE_DOWNWARD
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case FE_DOWNWARD:
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return (c == UNDERFLOW_EXCEPT_UPWARD
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|| c == UNDERFLOW_ONLY_DOWNWARD_ZERO);
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#endif
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#ifdef FE_TOWARDZERO
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case FE_TOWARDZERO:
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return true;
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#endif
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#ifdef FE_UPWARD
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case FE_UPWARD:
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return (c == UNDERFLOW_EXCEPT_DOWNWARD
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|| c == UNDERFLOW_ONLY_UPWARD_ZERO);
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#endif
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default:
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return (c == UNDERFLOW_EXCEPT_UPWARD
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|| c == UNDERFLOW_EXCEPT_DOWNWARD);
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}
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}
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else
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return true;
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}
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static bool support_underflow_exception = false;
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volatile double d = DBL_MIN;
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volatile double dd;
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static bool
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test_got_fe_underflow (void)
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{
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#ifdef FE_UNDERFLOW
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return fetestexcept (FE_UNDERFLOW) != 0;
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#else
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return false;
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#endif
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}
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#define TEST_STRTOD(FSUF, FTYPE, FTOSTR, LSUF, CSUF) \
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static int \
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test_strto ## FSUF (int i, int rm, const char *mode_name) \
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{ \
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const char *s = tests[i].s_ ## FSUF; \
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enum underflow_case c = tests[i].c; \
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int result = 0; \
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feclearexcept (FE_ALL_EXCEPT); \
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errno = 0; \
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FTYPE d = strto ## FSUF (s, NULL); \
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int got_errno = errno; \
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bool got_fe_underflow = test_got_fe_underflow (); \
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char buf[FSTRLENMAX]; \
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FTOSTR (buf, sizeof (buf), "%a", d); \
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printf ("strto" #FSUF \
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" (%s) (%s) returned %s, errno = %d, " \
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"%sunderflow exception\n", \
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s, mode_name, buf, got_errno, \
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got_fe_underflow ? "" : "no "); \
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bool this_expect_underflow = expect_underflow (c, rm); \
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if (got_errno != 0 && got_errno != ERANGE) \
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{ \
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puts ("FAIL: errno neither 0 nor ERANGE"); \
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result = 1; \
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} \
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else if (this_expect_underflow != (errno == ERANGE)) \
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{ \
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puts ("FAIL: underflow from errno differs from expectations"); \
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result = 1; \
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} \
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if (support_underflow_exception \
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&& got_fe_underflow != this_expect_underflow) \
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{ \
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puts ("FAIL: underflow from exceptions " \
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"differs from expectations"); \
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result = 1; \
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} \
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return result; \
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}
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GEN_TEST_STRTOD_FOREACH (TEST_STRTOD)
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static int
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test_in_one_mode (size_t i, int rm, const char *mode_name)
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{
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return STRTOD_TEST_FOREACH (test_strto, i, rm, mode_name);
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}
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static int
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do_test (void)
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{
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int save_round_mode __attribute__ ((unused)) = fegetround ();
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int result = 0;
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#ifdef FE_TONEAREST
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const int fe_tonearest = FE_TONEAREST;
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#else
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const int fe_tonearest = 0;
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# if defined FE_DOWNWARD || defined FE_TOWARDZERO || defined FE_UPWARD
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# error "FE_TONEAREST not defined, but another rounding mode is"
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# endif
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#endif
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#ifdef FE_UNDERFLOW
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feclearexcept (FE_ALL_EXCEPT);
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dd = d * d;
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if (fetestexcept (FE_UNDERFLOW))
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support_underflow_exception = true;
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else
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puts ("underflow exception not supported at runtime, only testing errno");
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#endif
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for (size_t i = 0; i < sizeof (tests) / sizeof (tests[0]); i++)
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{
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result |= test_in_one_mode (i, fe_tonearest,
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"default rounding mode");
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#ifdef FE_DOWNWARD
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if (!fesetround (FE_DOWNWARD))
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{
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result |= test_in_one_mode (i, FE_DOWNWARD,
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"FE_DOWNWARD");
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fesetround (save_round_mode);
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}
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#endif
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#ifdef FE_TOWARDZERO
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if (!fesetround (FE_TOWARDZERO))
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{
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result |= test_in_one_mode (i, FE_TOWARDZERO,
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"FE_TOWARDZERO");
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fesetround (save_round_mode);
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}
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#endif
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#ifdef FE_UPWARD
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if (!fesetround (FE_UPWARD))
|
|
{
|
|
result |= test_in_one_mode (i, FE_UPWARD,
|
|
"FE_UPWARD");
|
|
fesetround (save_round_mode);
|
|
}
|
|
#endif
|
|
}
|
|
return result;
|
|
}
|
|
|
|
#define TEST_FUNCTION do_test ()
|
|
#include "../test-skeleton.c"
|